The invention relates to a locking tongue for a seat belt comprising an inserting portion adapted to be inserted into a belt buckle and a deflecting portion for webbing, wherein the deflecting portion includes a webbing passage and a damping element for the webbing and wherein the clamping element is displaceable between a home position in which the webbing is freely movable and a blocking position in which the damping element is displaced against a wall of the webbing passage so that the webbing is clamped between the clamping element and the wall of the webbing passage, with the clamping element having a damping surface which in the blocking position damps the webbing against the wall of the webbing passage.
The invention further relates to a method of manufacturing such locking tongue.
In three-point belts looking tongues form a deflection point between a first portion of the seat belt which in the case of restraint restrains the pelvis of the vehicle occupant and a second portion which protects the upper body of the vehicle occupant against a forward out-of-position movement. The locking tongue is threaded with the defecting portion onto the webbing of the seat belt so that the locking tongue may be displaced freely along the webbing. This helps to adapt the length of the two portions of the seat belt to the vehicle occupant during buckling. In addition, by displacing the webbing by the locking tongue the webbing may be orientated so that it is in uniform contact with the vehicle occupant.
In the case of restraint the upper body may happen to move forward while the seat belt is blocked. Since the webbing is movably guided in the locking tongue, the webbing may be displaced so that the portion adjacent to the upper body is lengthened and the portion adjacent to the pelvis is shortened, thus causing the seat belt to constrict the pelvis area.
In order to prevent this, locking tongues include, for example, clamping elements which upon blocking of the seat belt may be displaced between a home position in which the webbing is freely movable and a blocking position in which the damping element clamps the webbing to the locking tongue so that no displacement of webbing is possible between the first and second portions of the seat belt. The pelvis area is thus protected against constricting by the seat belt and the upper body is protected against excessive forward out-of-position movement.
In the known locking tongues the webbing passage in which the clamping element is moved in the blocking position extends transversely to the longitudinal direction of the locking tongue. In the case of restraint the webbing is forced against the clamping element by the tensile force acting on the webbing. When the webbing is displaced relative to the locking tongue, for example by increased tension acting on the upper body portion, the damping element is drawn into the webbing passage by the webbing due to the increased friction between the clamping element end the webbing, until the clamping element blocks the webbing. In said locking tongues the clamping element is moved only when the webbing is moved in the locking tongue.
From the state of the art moreover locking tongues are known which include a clamping element which is movably arranged at an acute angle with respect to the webbing passage and, resp., with respect to the longitudinal direction of the locking tongue. Said locking tongues may be inserted in the webbing passage independently of the movement of the webbing, for instance by a tensile force of the webbing acting on the clamping element.
Both embodiments have the drawback, however, that the clamping element is drawn into the webbing passage by the tensile force acting on the webbing and gets jammed there. Hence the clamping element may get jammed in the webbing passage. It is frequently only possible to release the blocking by pulling the webbing into the opposite direction and thus moving the clamping element out of the blocking position back into the home position.